Editor's note: The U.S. State Department issued this travel warning on November 23, which we are running in full below. For our analysis of this week's travel risks and trends, read our special report on holiday travel.

The State Department alerts U.S. citizens to possible risks of travel due to increased terrorist threats. Current information suggests that ISIL (aka Da’esh), al-Qa’ida, Boko Haram, and other terrorist groups continue to plan terrorist attacks in multiple regions. These attacks may employ a wide variety of tactics, using conventional and non-conventional weapons and targeting both official and private interests. This Travel Alert expires on February 24, 2016.

Authorities believe the likelihood of terror attacks will continue as members of ISIL/Da’esh return from Syria and Iraq. Additionally, there is a continuing threat from unaffiliated persons planning attacks inspired by major terrorist organizations but conducted on an individual basis. Extremists have targeted large sporting events, theaters, open markets, and aviation services. In the past year, there have been multiple attacks in France, Nigeria, Denmark, Turkey, and Mali. ISIL/Da’esh has claimed responsibility for the bombing of a Russian airliner in Egypt.

U.S. citizens should exercise vigilance when in public places or using transportation. Be aware of immediate surroundings and avoid large crowds or crowed places. Exercise particular caution during the holiday season and at holiday festivals or events. U.S. citizens should monitor media and local information sources and factor updated information into personal travel plans and activities. Persons with specific safety concerns should contact local law enforcement authorities who are responsible for the safety and security of all visitors to their host country. U.S. citizens should:

Follow the instructions of local authorities. Monitor media and local information sources and factor updated information into personal travel plans and activities.

Be prepared for additional security screening and unexpected disruptions.

Stay in touch with your family members and ensure they know how to reach you in the event of an emergency.

Foreign governments have taken action to guard against terrorist attacks, and some have made official declarations regarding heightened threat conditions. Authorities continue to conduct raids and disrupt terror plots. We continue to work closely with our allies on the threat from international terrorism. Information is routinely shared between the United States and our key partners in order to disrupt terrorist plotting, identify, and take action against potential operatives, and strengthen our defenses against potential threats.

For further information: See the State Department's travel website for the Worldwide Caution, Travel Warnings, Travel Alerts, and Country Specific Information. Enroll in the Smart Traveler Enrollment Program (STEP) to receive security messages and make it easier to locate you in an emergency. Call 1-888-407-4747 toll-free in the United States and Canada or 1-202-501-4444 from other countries from 8 a.m. to 8 p.m. Eastern Standard Time, Monday through Friday (except U.S. federal holidays). Follow us on Twitter and Facebook.